This application claims priority under 35 U.S.C. xc2xa7 119 on Application No. 2001-272568, filed in Japan on Sep. 7, 2001.
1. Field of the Invention
The present invention relates to a hydraulic steering damper apparatus for a motorcycle used for suppressing the oscillation of a handle upon running. More particularly, the present invention relates to an apparatus which produces a variable damping force.
2. Description of Background Art
To prevent the oscillation of handle due to kick-back upon external perturbations, a hydraulic steering damper apparatus which produces a damping force to the oscillation is known (as an example, Japanese Patent No. 2593461). Furthermore, an apparatus for producing a variable damping force arranged to produce a damping force only when necessary, while not to produce the damping force in other cases, is known. For example, an apparatus which performs control based on a steering angle and a running speed (Japanese Published Unexamined Patent Application No. Sho 63-64888) and an apparatus which performs control based on a change in load on a front wheel (Japanese Published Examined Patent Application No. Hei 7-74023) are known.
In the steering damper utilizing hydraulic pressure as described above, even if generation of a damping force is controlled in correspondence with an external force inputted to the handle upon external perturbations and the like, the damping force changes due to a change in temperature of a working liquid. Accordingly, to precisely control the damping force, correction based on a change in temperature of the working liquid is required. However, any hydraulic steering damper in consideration of such correction has not been known. Furthermore, to measure the change in liquid temperature of the working liquid, it is necessary to provide a measurement device requiring a complicated structure, which increases the number of parts and costs.
Accordingly, the present invention has an object to provide a steering damper which can easily temperature-correct the damping force without such difficulty.
To solve the above problem, according to a first aspect of the present invention, a steering damper in a hydraulic steering damper apparatus applies a variable damping force to a rotation operation of a front wheel steering system supported by a vehicle body front part, wherein a value of said damping force is corrected based on a temperature measured by a temperature sensor provided in a predetermined position of said vehicle body.
According to a second aspect of the present invention said temperature sensor is provided for measurement of intake air temperature around an intake device.
According to the first aspect of the present invention, the damping force can be temperature-controlled based on the temperature measured by the temperature sensor provided in the predetermined position of the vehicle body. Therefore, the damping force can be corrected in correspondence with temperature change of the working liquid. Accordingly, the damping force can correspond more appropriately to an actual temperature.
In addition, the amount of heat generation of the steering damper itself is small, and the liquid temperature of the working liquid can be predicted from surrounding temperature outside the steering damper. Accordingly, the liquid temperature of the working liquid in the steering damper is not directly measured but the temperature measured by the temperature sensor provided in a different place from that of the steering damper in the vehicle body can be used. Accordingly, a complicated particular measurement device can be omitted, and the temperature detection can be simplified.
According to the second aspect of the present invention, the intake temperature sensor which is indispensable in, e.g. an electronic fuel injection system is utilized and its temperature information is used. Accordingly, any special temperature sensor for steering damper is not necessary. This improves the efficiency of use of parts, and reduces the number of parts and costs.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.